dd 


EXCHANGE 


Hspbaltum 


Scientific  Department 
Bulletin  iRo.  2 


Witabelpbfa 
flfeuseums 


Hspbaltum 


Scientific  department 
Bulletin  IRo.  2 


1900 


BOARD  OP  TRUSTEES. 


HON.  WILLIAM  A.  STONE, 
Governor  of  Pennsylvania. 

HON.  SAMUEL  H.  ASHBRIDGE, 
Mayor  of  Philadelphia. 

JAMES  L.  MILES, 
President  of  Select  Council. 

GEORGE  McCURDY, 
President  of  Common  Council. 

SAMUEL  B.  HUEY, 
President  of  the  Board  of  Public  Education. 

DR.  NATHAN  C.  SCHAEFFER, 
State  Superintendent  of  Public  Instruction. 

DR.  EDWARD  BROOKS, 
Superintendent  of  Public  Schools. 

DR.  J.  T.  ROTHROCK, 
State  Forestry  Commissioner. 

CHARLES  H.  CRAMP, 

DANIEL  BAUGH,  THOMAS  MEEHAN, 

THOMAS  DOLAN,  J.  C.  STRAWBRIDGE, 

GEORGE  F.  EDMUNDS,  CHARLES  F.  WARWICK, 

WILLIAM  L.  ELKINS,  JOHN  WANAMAKER, 

W.  W.  FOULKROD,  P.  A.  B.  WIDENER,  ' 

SIMON  GRATZ,  SYDNEY  L.  WRIGHT, 

BUS..CORNELIUS  STEVENSON. 


OFFICERS 

OF  THE 

BOARD  OF  TRUSTEES. 


JUSTUS  C.  STRAWBRIDGE, 
President. 

CHARLES  F.  WARWICK, 
Vice-President. 

DANIEL  BAUGH, 

Treasurer. 

BENJAMIN  W.  HANNA, 
Secretary. 


OFFICERS  OF  THE  MUSEUMS, 


WM.  P.  WILSON, 
Director. 

WILLIAM  HARPER, 
Chief,  Bureau  of  Information. 

C.  A.  GREEN, 
Assistant  Chief,  Bureau  of  Information. 

DUDLEY  BARTLETT, 
Assistant  Chief,  Bureau  of  Information. 

WILFRED  H.  SCHOFF, 
Chief,  Foreign  Department. 

GUSTAVE  NIEDERLEIN, 
Chief,  Scientific  Department. 

WILLIAM  B.  MARSHALL, 
Curator  of  Natural  Products. 

ERNST  FAHRIG, 
Chief  of  Laboratories. 

E.  W.  S.  TINGLE, 
Assistant  to  the  Director. 


382236 


(Commercial 


The  Philadelphia  Commercial  Museum  is  a  public  institution 
devoted  to  the  general  extension  of  international  commerce.  It 
is  maintained  by  the  City  of  Philadelphia  and  by  private  sub- 
scriptions from  business  firms.  It  is  not  local  in  its  objects,  but 
works  for  all  sections  of  the  country,  and  has  received  the  sanc- 
tion and  financial  assistance  of  the  State  of  Pennsylvania  and  the 
United  States  Government.  Its  high  standing  and  reputation 
are  due  to  the  fact  that  it  does  not  enter  into  actual  trade  of  any 
kind  and  is  in  no  way  affiliated  with  any  political  organization. 
Its  advice  is  always  absolutely  impartial  and  without  private 
interest.  It  has  no  sources  of  revenue  upon  which  profits  may 
accrue,  as  all  service  rendered  to  individuals  is  recompensed  on 
the  basis  of  actual  cost.  To  its  large  and  busy  offices  and  exhi- 
bition halls,  over  its  threads  of  business  communication  stretching 
out  to  every  commercial  center  in  the  world,  come  constant 
reports  of  trade  conditions  and  opportunities,  changes  in  the 
condition  of  business  firms,  new  developments  offering  profit  to 
idle  capital,  and  new  natural  products  of  probable  utility  in 
manufacturing  industries.  It  is  a  center  of  commercial  informa- 
tion, in  equally  close  connection  with  business  houses  all  over 
the  world,  to  which  reports  and  confidential  advices  are  regularly 
and  systematically  issued;  a  confidential  adviser  in  opening  up 
new  markets  for  all  useful  natural  or  manufactured  products;  a 
special  mercantile  bureau  with  connections  in  all  foreign  coun- 
tries, reporting  not  only  the  general  standing  of  firms,  but  their 
disposition  and  fitness  to  handle  particular  agencies;  a  business 
institution  run  by  business  men,  yet  carrying  on  no  private  trans- 
actions. A  manufacturer  or  merchant  in  the  United  States,  a 
producer  or  exporter  abroad,  an  importer,  retailer  or  selling 
agent  in  some  far  off -land — all  these  apply  with  equal  confidence 


for  the  advice  of  the  Institution;  and  the  advice  is  always  given 
with  the  same  impartiality  and  care,  though  to  do  so  investiga- 
tions be  required  at  the  ends  of  the  earth.  No  similar  institution 
or  association  in  the  world  wields  an  influence  equal  to  that  of 
the  Philadelphia  Commercial  Museum. 

The  first  aim  and  object  of  the  Museum  is  to  foster  and 
promote,  by  practical  and  systematic  efforts,  and  by  new,  original 
and  effective  methods,  the  foreign  trade  of  America.  In  this 
work  it  has  the  support  of  an  Advisory  Board,  comprising  repre- 
sentatives of  the  leading  Chambers  of  Commerce  and  similar 
organizations  in  the  United  States  as  well  as  in  foreign  countries. 
It  also  has  the  benefit  of  similar  advice  from  an  honorary  Diplo- 
matic Board,  comprising  the  Ministers  of  many  of  the  foreign 
countries  resident  in  Washington.  It  is  in  constant  communica- 
tion with  over  20,000  foreign  correspondents,  through  whom  it 
keeps  in  touch  with  every  possible  phase  of  international  com- 
merce. This  extensive  correspondence  is  carried  on  in  more 
than  a  dozen  different  languages. 

A  merchant  or  manufacturer  who  wishes  to  trade  in  a  foreign 
market  must  first  know,  specifically,  the  nature  and  value  of  that 
market.  Granted  that  its  trade  will  repay  the  effort  of  securing 
it,  he  must  know  exactly  what  the  market  requires,  what  it  can 
offer  in  return,  what  business  houses  to  deal  with,  and  what  are 
the  conditions  on  which  business  is  customarily  done. 

The  activity  of  the  Museum  is  specifically  directed  to  meet 
these  various  requirements  by  exhaustive  commercial  reports, 
which  are  further  illustrated  by  collections  of  trade  samples,  both 
natural  and  manufactured.  To  the  general  business  community 
the  resources  are  made  available  by  the  Bureau  of  Information. 
This  Bureau  is  actively  reporting  trade  conditions  existing  in 
other  countries  to  leading  manufacturers  and  merchants  in  every 
part  of  the  United  States.  Complete  and  detailed  reports  as  to 
the  demand  of  every  market  in  the  world,  the  style  of  goods 
required,  method  of  purchase  and  shipment,  customs,  of  receipt 
and  sale,  are  all  fully  described  to  intending  shippers,  and  every 
possible  assistance  is  given  them,  not  only  in  the  proper  prepara- 
tion and  forwarding  of  their  goods,  but  in  the  most  advantageous 
way  of  -approaching  possible  buyers  with  a  view  to  securing 
orders.  Through  an  extensive  and  well-equipped  Bureau  at- 
tached to  the  Museum,  accurate  and  reliable  reports  are  on  file 


Ill 

and  readily  attainable,  regarding  the  standing  and  reputation  of 
possible  buyers  in  every  country  in  the  world,  thereby  rendering 
trade  with  other  nations  no  more  hazardous  than  trade  in  the 
home  market. 

The  Museum  is  promptly  informed,  through  ilts  agents  and 
representatives,  of  all  important  enterprises  in  other  countries — 
government  contracts,  tenders  for  public  works,  which  are  re- 
ferred to  probable  American  bidders  through  a  special  News 
Bureau. 

The  trade  literature  of  the  world  is  gathered  into  a  special 
library.  Here  will  be  found  hundreds  of  trade  and  technical 
journals,  in  fully  twenty  languages,  together  with  shipping  and 
market  reports,  statistical  publications  of  all  countries,  export 
and  import  manifests,  etc. 

This  information  is  indicated  by  a  card-catalogue  system, 
and  every  fact  that  has  practical  business  value  finds  its  way  at 
once  into  the  hands  of  a  body  of  experts,  who  include  it  at  once 
in  the  individual  reports. 

An  elaborate  system  of  reporting  on  the  specific  require- 
ments of  business  houses  in  other  countries  has  been  established, 
whereby  the  complete  statements  of  responsible  houses  are  issued 
on  index  cards  and  distributed  to  manufacturers  and  exporters  in 
all  parts  of  the  country,  who  hold  confidential  cabinets  of  such 
cards  placed  in  their  hands  by  the  Museum.  In  this  way  there 
is  furnished  a  reliable  directory  of  foreign  buyers  specially  pre- 
pared for  each  individual  manufacturer. 

The  collections  of  trade  samples  belonging  to  the  Museum, 
which  are  used  to  illustrate  and  extend  the  work  instituted  by 
the  commercial  reporting,  are  classified  under  the  following 
heads: 

Manufactured  Articles— 

(#)   Arranged  in  lines  of  manufacture. 

Raw  Products — 

(a)  Geographic  arrangement  of  collections. 

(b)  Monographic  arrangement  of  collections. 

The  Museum  shows  the  consuming  capacity  of  any  given 
country  by  collections  of  the  goods  that  are  most  saleable  there. 
These  are  actual  samples  of  what  is  in  the  market,  selected  with 
great  care  by  experts  of  the  Museum.  Textiles,  hardware, 


clothing,  household  goods,  cutlery,  provisions — everything  that 
is  imported — are  represented  in  these  sample  collections.  With 
each  sample  is  found  full  information  as  to  place  of  manufacture, 
price,  terms  of  sale,  distribution,  etc.  These  collections  are  con- 
stantly renewed  and  extended. 

Having  shown  the  consuming  capacity,  the  Museum  then 
shows  the  producing  capacity  by  collections  of  natural  products. 

These  show  at  a  glance  what  is  produced  by  any  given 
country,  and  what  it  has  to  offer  in  the  way  of  a  return  trade. 
These  collections  are  made  practically  useful  by  scientific  and 
technical  laboratories  in  which  complete  tests  are  made,  with 
special  reference  to  the.  industrial  value  of  any  given  product. 
The  usefulness  of  this  work  is  well  established  in  many  countries, 
and  merchants  are  constantly  sending  samples  of  exportable 
products,  in  order  that  the  Museum  may  report  on  their  useful- 
ness for  the  American  market. 


ASPHALTUM. 


Asphaltum  is  a  bituminous  mineral  substance  of  somewhat  the  same 
nature  and  appearance  as  pitch.  It  is  black  to  brownish-black  in  color  and 
often  occurs  mixed  with  clay,  sand  or  vegetable  matter,  or  impregnating 
beds  of  sandstone,  limestone  or  shale.  The  solid  varieties,  or  true  asphal- 
tums,  soften  under  a  moderate  heat  and  melt  at  about  90°  to  100°  C.  (194° 
to  212°  F. ).  Most  kinds  burn  readily  with  a  sooty  flame  and  a  strong  bitu- 
minous odor. 

In  addition  to  solid  asphaltums,  there  are  more  or  less  liquid  varieties  of 
a  viscous  nature,  which  approach  the  heavy  petroleums  in  character,  com- 
position and  properties,  and  seem  to  have  been  derived  from  them. 

Natural  bituminous  substances  may  be  conveniently  classified  as  follows: 

1.  Liquid  (petroleum). 

2.  Viscous  (liquid  asphalt  or  maltha). 

3.  Solid  (asphaltum  or  mineral  pitch). 

So  many  substances  are  found  intermediate  between  these  types  that  the 
boundary  lines  between  them  are  very  indefinite. 

NOMENCLATURE. 

Liquid  asphalts  are  variously  called  maltha,  mineral  tar,  brea,  and 
pittasphalt. 

Solid  asphalts  are  called  asphaltum,  natural  bitumen,  native  bitumen, 
mineral  pitch,  brea  (Spanish),  asphalte  or  bitume  (French),  bergpech  or 
erdpech  (German).  "  Manjak,"  glance  pitch  and  gum  asphaltum  are 
names  applied  to  very  pure  varieties.  "  Chapapote  "  is  a  variety  from  Cuba. 

The  names  of  some  very  pure  hydrocarbons  which  are  nearly  related  to 
and  are  often  classed  as  asphalts  are  ozocerite  (or  ozokerite),  uintahite, 
gilsonite,  wurtzilite,  grahamite,  albertite,  lithocarbon,  and  elaterite. 

Asphaltum  from  Trinidad  is  called  Trinidad  asphalt,  Trinidad  pitch, 
lake  pitch,  and  land  pitch. 

Rocks  containing  asphaltum  are  called  rock  asphalt,  asphalt  rock, 
bituminous  or  asphaltic  sandstone,  bituminous  limestone,  bituminous  shale, 
etc.  In  Europe  there  has  been  an  effort  to  restrict  the  use  of  the  term 
asphalt  to  what  in  this  country  are  called  rock  asp  tilts 


CHEMISTRY. 

Chemically  no  dividing  line  can  be  drawn  between  the  liquid,  viscous 
and  solid  bitumens  on  account  of  the  many  substances  intermediate  between 
them,  and  hence,  in  the  study  of  asphaltums,  we  must  necessarily  consider 
petroleum  to  some  extent.  Petroleum  consists  chiefly  of  members  of  the 
paraffin  or  marsh-gas  series  of  hydrocarbons  (of  the  general  formula 
CnH2n+2),  and  contains  a  considerable  percentage  of  oils  vaporizable  at 
100°  C.  (212°  F.)  or  below;  defines  and  benzenes  are  usually  present,  and 
sometimes  the  solid  paraffins. 

Asphaltum,  according  to  Dana  (System  of  Mineralogy,  1895),  contains 
the  following  classes  of  ingredients: 

(a)  Oils  vaporizable  at  100°  C.  or  below;  sparingly  present,  if  at  all. 

(b)  Heavy  oils,  probably  of  the  pittolium  or  petrolene  groups;  vapor- 
izable between  100°  and  250°  C.;  constituting  sometimes  85  per  cent,  of  the 
mass. 

(c)  Resins  soluble  in  alcohol. 

(d)  Solid  asphalt-like  substance  or  substances  soluble  in  ether  and  not 
in  alcohol;  black,  pitch-like,  lustrous  in  fracture;  15  to  85  per  cent. 

(e)  Black  or  brownish-black  substance  or  substances  not  soluble  either 
in  alcohol  or  ether;  i  to  75  per  cent. 

(f )  Nitrogenous  substances,  often  as  much  as  corresponds  to  i  or  2  per 
cent,  of  nitrogen. 

All  varieties  of  asphaltum  are  wholly  or  partly  soluble  in  one  or  more  of 
the  following  solvents,  viz.:  carbon  bisulphide,  alcohol,  ether,  chloroform, 
turpentine,  petroleum,  naptha,  and  benzene. 

The  ingredients  which  compose  asphaltums  are  present  in  varying  pro- 
portions in  different  kinds  of  asphaltum,  and  are  classified  by  different 
authors  in  many  ways. 

A  convenient  mode,  and  one  in  frequent  use,  is  a  division  into  petro- 
lene and  asphaltene  as  proposed  by  Boussingault.  Petrolene  he  described 
as  an  oil  ( C10H16) ,  separable  from  asphalt  by  heating  in  an  oil-bath  to  300°  C. 
(572°  F.),  asphaltene  being  the  residue.  There  can  be  no  doubt  that  these 
are  mixtures  of  various  substances,  and  not  simple  compounds  as  described, 
still  the  classification  is  found  very  useful.  Petrolene  embraces  the  more 
volatile  and  liquid  ingredients  and  is  the  part  which  gives  to  asphaltum  its 
cementing  power.  Asphaltene  consists  of  the  solid  ingredients  and  imparts 
firmness  and  stiffness.  The  relative  proportion  of  these  two  ingredients 
determines  largely  the  nature  of  any  asphaltum.  Too  much  petrolene  ren- 
ders it  soft,  while  too  much  asphaltene  makes  it  lack  plasticity  and  cement- 
ing power,  causing  brittleness. 

Just  enough  petrolene  should  be  present  to  hold  all  the  asphaltene  in 
complete  solution.  The  liquid  asphaltums  contain  a  large  percentage  of 
petrolene. 

DISTRIBUTION. 

Asphaltums  are  found  in  many  places — all  over  the  globe.  The  greatest 
deposit  is  the  so-called  "  Pitch  Lake,"  in  the  southwestern  part  of  the  island 
of  Trinidad,  and  consists  of  bitumen  mixed  w7ith  earthy  and  organic  matter. 


The  Pitch  Lake  is  about  114  acres  in  extent,  138  feet  above  sea-level,  and  a 
mile  and  a  quarter  from  the  seashore.  It  occupies  a  saucerlike  depression 
more  than  2300  feet  across  the  center.  A  boring  135  feet  deep  did  not  reach 
the  bottom  of  the  deposit.  Numerous  borings  nearer  to  the  edge  have  shown 
that  the  rock  under  the  asphalt  is  a  sandstone  more  or  less  impregnated  with 
bitumen.  It  is  usually  stated  that  this  depression  in  which  the  asphaltum  is 
found  is  the  crater  of  an  extinct  volcano,  but  there  seems  to  be  no  indication 
of  this,  except  the  shape  of  the  deposit,  and  the  fact  that  the  asphalt  is  in  a 
state  of  continual  agitation  due  to  the  ebullition  of  gases.  The  generation 
of  these  gases  is  more  likely  caused  by  chemical  reactions  in  the  asphalt  as 
it  changes  from  soft  to  harder  form,  than  by  volcanic  action,  and  at  present 
there  is  no  better  reason  to  suppose  that  this  pitch  lake  occupies  the  crater 
of  an  ancient  volcano  than  to  suppose  that  many  lakes  which  receive  con- 
stant supplies  of  water  from  springs  in  the  bottom,  occupy  volcanic  craters. 
The  surface  of  the  lake  is  fairly  level,  but  uneven,  the -asphalt  Occurring  in 
spherical  or  mushroomlike  masses  of  irregular  shape,  varying  from  30  to  200 
feet  across.  The  spaces  between  the  masses  of  asphalt  are  filled  with  water, 
and  there  is  said  to  be  a  constant  slow  suction  of  this  water  from  below  and 
of  the  asphalt  near  the  water,  with  a  corresponding  upward  and  lateral 
motion  of  the  asphalt  in  the  middle  of  the  mass.  Most  of  the  lake  is  so  solid 
that  horses  and  carts  are  driven  over  it  with  perfect  safety,  but  in  some 
places  the  asphalt  is  soft  and  viscous.  Carbon  dioxide  and  sulphuretted 
hydrogen  gases  are  constantly  evolved  in  the  soft  asphalt,  and  the  pitch  as 
it  is  dug  always  contains  cavities  which  have  been  filled  with  these  or  other 
gases.  A  small  railroad  is  built  on  the  lake  for  the  removal  of  the  asphalt, 
which  is  taken  from  within  a  foot  or  two  of  the  surface  by  negroes  or 
imported  East  Indian  coolies  working  with  picks  and  shovels.  In  the  course 
of  a  few  months,  fresh  material,  slowly  rising,  fills  up  any  excavations,  and 
the  inflow,  which  has  been  estimated  at  20,000  tons  per  year,  is  so  rapid  that 
it  is  very  difficult  to  dig  pits  over  ten  or  twelve  feet  in  depth.  The  thickness 
of  the  deposit  has  been  variously  estimated  at  from  18  feet  to  133  feet.  The 
asphaltum  from  this  lake  is  known  in  commerce  as  Trinidad  lake  pitch, 
and  is  of  very  uniform  quality.  Land  pitch  is  a  poorer  grade,  mixed  with 
considerable  earth;  it  is  found  near-by,  and  has  evidently  been  derived 
from  an  overflow  of  the  lake  at  some  time  in  the  past.  Fluid  bitumen, 
oozing  from  the  bottom  of  the  sea  and  floating  on  the  surface,  has  been 
observed  on  both  sides  of  the  island  of  Trinidad. 

Other  deposits  of  the  same  nature  or  of  pure  bitumen,  are  found  at  .many 
places  in  the  West  Indies  and  in  the  northern  part  of  South  America. 

One  very  large  deposit,  said  to  be  inexhaustible,  is  on  the  island  of 
Pedernales,  at  the  mouth  of  the  Orinoco  River.  This  asphalt  is  found  as  a 
thick  black  viscous  mass,  containing  a  large  percentage  of  volatile  oils  and 
considerable  water,  but  almost  no  mineral  impurities. 

Bermudez  asphalt,  which  comes  from  near  Maturin  in  Venezuela,  con- 
tains very  little  mineral  matter  and  a  large  amount  of  easily  volatile  oils. 
The  asphalt,  which  is  from  7  to  9  feet  deep,  is  exuded  by  springs,  and  a  large 
part  of  the  deposit  is  covered  with  a  rank  vegetation;  it  has  been  used  to 
some  extent  in  this  country  for  paving.  Large  beds  of  asphalt  are  found 


near  Maracaibo,  Merida,  Coro,  and  other  places  in  Venezuela,  and  in  Colom- 
bia. Extensive  deposits,  most  of  them  entirely  undeveloped,  are  known  to 
occur  in  Cuba,  in  the  provinces  of  Havana,  Pinar  del  Rio,  Bahia  Honda,  and 
Matanzas.  At  Cardenas  there  are  "mines  "  in  the  bay  from  which  superior 
asphalt  has  been  obtained  by  dredging  in  water  twelve  feet  or  more  in  depth. 
Asphalt  occurs  in  other  West  India  islands,  notably  Barbadoes.  It  has  been 
found  in  Mexico  and  in  Central  America. 

Small  quantities  of  a  fine  grade  of  asphalt  have  come  from  Caxatambo, 
Peru. 

It  is  found  in  Alsace  and  Brunswick,  Germany;  at  Chieta,  Italy; 
Auvergne,  France;  in  Hungary;  in  Russia;  at  Salonica,  Turkey;  near  Bey- 
root,  and  in  the  neighborhood  of  the  Dead  Sea,  in  Syria;  and  near  the  site 
of  Babylon. 

It  has  been  observed  in  Egypt,  in  Algeria,  and  on  the  lower  Congo. 

Extensive  beds  of  rock  asphalt  are  found  in  Europe.  Nearly  all  of 
these  are  composed  of  bituminous  limestone.  The  principal  mines  are  at 
Seyssel,  Department  de  1'Arii,  France;  Val  de  Travers,  Neufchatel,  Switzer- 
land; Ragusa,  Sicily;  and  Vorwohle  and  Limmer,  Germany.  At  Seyssel 
there  are  eight  strata  of  bituminous  limestone,  separated  by  layers  of  ordinary 
white  limestone. 

One  of  these  strata  of  asphalt  rock,  about  100  feet  above  the  level  of 
the  Rhone,  is  23  feet  thick,  and  galleries  are  dug  in  it  reaching  more  than 
seven  miles  in  length.  This  is  the  largest  known  bed  of  asphaltic  limestone. 

Other  deposits  of  rock  asphalt  are  found  near  Alais,  France;  Mt. 
Laviano,  Salerno,  Italy;  Chieti,  Abruzzi,  Italy;  and  in  Austria.  Deposits  of 
bituminous  sandstone  are  found  in  Auvergne,  France;  and  at  Maestu,  Spain. 

In  the  United  States,  asphalt  is  found  in  many  places.  The  most 
extensive  known  deposits  are  in  California,  in  the  counties  of  Santa  Cruz, 
San  Luis  Obispo,  Los  Angeles,  Kern,  Monterey,  Ventura  and  Santa  Bar- 
bara, and  are  of  a  very  varied  character.  Most  of  the  material  is  bituminous 
sandstone,  ranging  from  very  fine  sand  particles  to  coarse  gravel,  in  many 
cases  with  a  large  percentage  of.  clay. 

Some  deposits  are  almost  entirely  lacking  in  sandy  matter  and  consist 
of  clay  or  shale,  and  in  one  case  the  base  is  an  infusorial  earth. 

At  Las  Conchas  Mine,  Santa  Barbara  County,  California,  there  is  an  im- 
mense deposit  of  liquid  asphaltum,  on  the  ocean  beach,  which  saturates  beds 
of  shale  known  to  be  400  feet  thick.  By  a  patent  process  of  extraction  the 
liquid  asphalt  is  obtained  from  an  immense  bed  of  sand  which  lies  on  top  of 
the  bed  of  shale.  There  is  a  continuous  upw?ard  flow  of  the  liquid  asphalt 
from  the  shale,  and  this  has  caused  its  presence  in  the  overlying  sand,  which 
is  very  free  from  clay  or  other  impurity.  Similar  beds  are  situated  under 
the  ocean,  and  the  upward  flow  of  the  asphalt  is  shown  by  an  oily  film  on 
the  water  for  many  miles.  At  La  Patera,  on  the  seashore,  twenty-five  miles 
west  of  the  Las  Conchas  Mine,  is  a  very  large  deposit  of  rock  asphalt. 
This  material  contains  about  60  per  cent,  of  bitumen  and  40  per  cent,  of 
very  fine  quartz  sand.  It  is  hard  and  brittle,  resembling  cannel  coal.  The 
mining  is  carried  on  by  drifts,  one  of  which  is  125  feet  underground. 
Ledges  extend  u'--kr  the  sea  and  to  a  distance  of  half  a  mile  inland,  and  the 


material  is  remarkably  homogeneous.  In  spite  of  its  apparent  solidity,  it  is 
constantly  forced  up  from  below,  in  one  instance  fifty-two  feet  having  been 
cut  off  from  the  floor  of  a  drift  in  one  year  as  the  asphalt  swelled  up.  A  mix- 
ture of  this  solid  asphalt  with  the  liquid  asphalt  previously  described  forms 
"Alcatraz  "  cement,  used  for  paving  and  other  purposes. 

In  Breckenridge,  Logan  and  Grayson  Counties,  Kentucky,  sandstones 
are  found  which  seem  to  consist  of  sand  particles  held  together  by  no  other 
cementing  material  than  the  bitumen.  The  sandstone  is  taken  out  by 
ordinary  methods  of  quarrying  and  used  for  paving.  The  bituminous  matter 
in  these  sandstones  has  apparently  been  derived  from  underlying  beds  of 
subcarboniferous  limestone.  Heavy  petroleum  and  mineral  tar  are  obtained 
in  small  quantities  from  many  springs  in  this  part  of  Kentucky.  Other 
deposits  of  bituminous  sandstone  occur  in  Oklahoma  and  the  Indian  Ter- 
ritory. 

Bituminous  limestones  are  found  in  Utah,  Indian  Territory,  and  Texas. 

Very  pure  hydrocarbons  called  gilsonite,  uintahite,  wurtzilite  and 
ozokerite,  all  of  them  of  them  often  referred  to  as  gum  asphaltuin,  are 
found  in  a  deposit  extending  through  parts  of  Uintah  and  Wasatch  Counties, 
in  Utah,  and  Rio  Blanco  County,  Colorado.  These  substances  vary  some- 
what in  composition  and  properties,  but  all  are  of  a  pure  nature,  brittle,  jet 
black  in  color,  and  with  a  brilliant,  pitchy  lustre. 

Ozocerite  (ozokerite,  mineral  wax,  or  native  paraffine)  is  generally  a 
brownish  or  reddish,  greasy  solid  of  the  consistency  of  wax;  it  is  found  in 
Galicia  and  Utah. 

Albertite  from  Nova  Scotia  and  grahamite  from  West  Virginia  are 
related  to  gilsonite. 

Elaterite  is  an  elastic  bitumen  from  Derbyshire,  England. 


EXPLANATION  OF  THE  MAP. 


LOCALITIES. 
ON  COASTS  OF  CARIBBEAN  SEA  AND  GULF  OF  MEXICO. 

TRINIDAD  ISLAND,  the  source  of  a  very  large  part  of  the  world's  supply 
of  asphaltum. 

VENEZUELA.— The  ISLAND  OF  PEDERNALES  and  MATURIN  are  important 
sources  of  commercial  asphaltum. 

At  other  places  in  VENEZUELA,  GUIANA,  COLOMBIA,  CENTRAL  AMERICA 
and  MEXICO  are  deposits  of  asphaltum  not  at  present  of  commercial  impor- 
tance. 

CUBA.— Large  deposits,  undeveloped.  Other  WEST  INDIA  ISLANDS, 
notably  BARBADOES. 

NORTH  AMERICA. 

CALIFORNIA. — The  southwestern  part  of  the  State  is  the  greatest  pro- 
ducing locality  outside  of  Trinidad,  and  contains  deposits  of  asphaltum, 
liquid  asphalt,  bituminous  sandstone,  and  bituminous  shale. 

UTAH  produces  uintahite  and  bituminous  limestone. 

Deposits  of  uintahite,  gilsonite,  etc.,  occur  in  COLORADO,  WYOMING 
and  MONTANA. 

Bituminous  limestone  is  found  in  INDIAN  TERRITORY,  OKLAHOMA  and 
TEXAS. 

Bituminous  sandstone  is  mined  in  KENTUCKY  and  TENNESSEE. 

Grahamite  occurs  in  WEST  VIRGINIA. 

Albertite  occurs  in  NOVA  SCOTIA. 

EUROPE. 

FRANCE  AND  SWITZERLAND. — Very  large  deposits  of  bituminous  lime- 
stone, mined  at  Seyssel,  France,  and  Val  de  Travers,  Switzerland,  and  at 
other  places. 

Similar  deposits  are  mined  in  SICILY,  ITALY,  and  Vorwohle  and  Limtner, 
GERMANY.  Purer  asphaltums  are  found  in  TURKEY,  RUSSIA,  AUSTRIA  and 
HUNGARY,  but  these  localities  are  not  commercially  important. 

Other  unimportant  localities  are  the  shores  of  the  CASPIAN  SEA,  the 
EUPHRATES  VALLEY,  the  DEAD  SEA,  ALGERIA,  the  region  of  the  lower 
CONGO  RIVER,  and  PERU. 


ORIGIN. 

Petroleum  and  asphaltum  are  so  closely  allied  in  their  chemical  nature 
and  by  intermediate  compounds,  approach  so  closely  in  their  physical  char- 
acteristics, and  are  so  connected  in  their  natural  mode  of  occurrence,  that  we 
must  consider  the  formation  of  petroleum  in  order  to  understand  that  of 
asphaltum.  As  far  as  our  observation  goes,  we  know  of  no  origin  of  asphal- 
tum other  than  the  oxidation  of  petroleum  with  the  escape  of  its  easily 
volatile  oils. 

Leading  geologists  now  agree  that  natural  bitumens  are  in  some  way  a 
product  of  the  decomposition  of  vegetable  or  vegetable  and  animal  sub- 
stances, but  under  just  what  circumstances  this  decomposition  has  taken 
place,  and  what  intermediate  stages  the  material  has  passed  through,  is  not 
well  understood,  and  the  theories  in  regard  to  these  points  are  very  varied. 

It  is  well  known  that  at  ordinary  temperatures,  out  of  contact  with  the 
atmosphere,  the  decay  of  vegetation  produces  marsh-gas  (CH4).  In  a  few 
places  in  the  world  large  beds  of  ancient  vegetation,  which  were  long  ago 
buried  in  or  under  beds  of  clay,  have  by  decomposition  yielded  natural  gas 
and  other  hydrocarbons  nearly  related  to  petroleum  and  asphaltum. 

By  destructive  distillation,  under  proper  conditions,  vegetable  and 
animal  substances  produce,  first,  gases,  then  easily  volatile  oils,  and  these  in 
turn  produce  less  volatile  oils  similar  to  petroleum,  substances  like  mineral 
tar  and  asphaltum,  and  these  being  made  by  a  continuation  of  the  same 
process,  pass  imperceptibly  from  one  form  to  another. 

Beds  of  vegetable  or  vegetable  and  animal  matter  exist  now  in  the  earth 
in  the  form  of  bituminous  clays,  shales,  sandstones  and  limestones,  peat 
bogs,  and  coal  beds.  Almost  all  of  these  formations,  by  destructive  distilla- 
tion in  the  laboratory,  can  be  made  to  yield  natural  gas  and  petroleum  in 
greater  or  less  amount.  It  is  frequently  very  difficult  to  tell  just  how  these 
beds  have  been  formed,  and  at  what  time,  or  in  what  way,  the  carboniferous 
materials  have  been  added  to  the  mineral  ingredients  of  the  bed. 

Some  good  authorities  assert  that  natural  gas  and  petroleum  have  in 
nearly  all  cases  originated  in  and  been  derived  from  bituminous  limestones, 
and  that,  when  found  in  or  associated  with  sandstones,  conglomerates  and 
shales,  the  bituminous  matter  has  been  derived  from  underlying  limestone 
deposits.  The  large  deposits  of  asphaltum  and  bituminous  sandstone  in  Cal- 
fornia  are  asserted  by  J.  D.  Whitney  to  have  been  derived  from  the  remains 
of  infusoria  in  limestone.  This  view  is  supported  by  the  fact  that  many 
bituminous  limestones  are  uniformly  bituminous  throughout  the  bed,  while 
many  of  the  deposits  of  bitumen  in  sandstone  are  superficial,  the  bitumen 
being  present  only  in  that  part  of  the  sandstone  which  is  comparatively  near 
to  a  bed  of  bituminous  limestone. 

The  supporters  of  this  theory  assert  that  when  petroleum  and  allied  sub- 
stances are  found  in  limestone,  they  are  a  result  of  primary  decomposition, 
while  in  other  rocks  they  occur  only  as  a  result  of  secondary  decomposition. 
In  many  instances,  the  truth  of  this  theory  seems  to  be  extremely  probable, 
yet  there  are  deposits  of  shales  and  sandstones  highly  impregnated  with 
bituminous  matter  which  seems  to  be  indigenous.  Such  a  deposit  is  in  Vene- 
zuela, near  the  mouth  of  the  Orinoco  River,  and  this  seems  to  throw  light  on 


the  formation  of  asphaltum  in  Venezuela  and  Trinidad.  This  deposit  con- 
sists of  recent  beds  of  shale  (belonging  to  the  later  Tertiary  age)  which 
•were  formed  under  the  sea,  and  contain  abundant  vegetable  remains  brought 
down  by  the  river.  These  beds  of  shale  have  been  raised  to  the  surface  by 
geological  action  and  are  now  3'ielding  quantities  of  petroleum  by  direct 
decomposition  of  the  vegetable  matter.  In  the  hot  climate,  exposed  to  the 
atmosphere,  the  petroleum  soon  changes  to  asphaltum. 

In  Tennessee  there  are  many  occurrences  in  sandstone,  of  oils  derived 
from  underlying  subcarboniferous  sandstone  and  not  traceable  to  limestone. 
These  oils  pass  by  natural  processes  of  oxidation  into  viscous  tar  or  maltha, 
and  further  into  solid  asphalt.  In  Scotland,  where  beds  of  coal  have  been 
penetrated  by  volcanic  dykes,  both  petroleum  and  asphalt  occur  in  seams 
and  fissures  in  the  coal  and  trap. 

In  the  artificial  production  of  asphaltum  from  organic  substances  by 
distillation,  it  is  necessary  to  apply  considerable  heat,  sometimes  over  400°  C. 
(752°  F.).  It  is  not  known  to  what  extent  heat  has  influenced  the  formation 
of  these  substances  in  nature.  Some  writers  think  they  were  formed  by  the 
action  of  intense  volcanic  heat  on  beds  of  organic  matter  in  the  earth,  pro- 
tected by  beds  of  rock  above. 

Other  authorities  think  the  distillation  took  place  slowly  at  a  low  tem- 
perature, some  even  referring  to  the  possibility  of  a  slow,  spontaneous  distil- 
lation, with  no  more  heat  than  that  caused  by  the  decomposition  of  the 
organic  material.  When  petroleum  has  been  derived  from  limestone,  the 
parent  rock  seldom  seems  to  have  been  acted  on  by  intense  heat. 

Some  writers  say  that  asphaltum  cannot  have  been  derived  from  petro- 
leum without  the  application  of  a  fairly  high  heat,  as  many  of  the  oils  present 
in  petroleum  and  lacking  from  asphalt,  are  not  volatile  at  low  temperatures. 
In  contradiction  of  this,  we  see  in  nature  thick  viscous  tar  and  fairly  solid 
asphalt  formed  by  the  slow  oxidation  of  quite  liquid  petroleum  in  the  atmos- 
phere at  ordinary  temperatures. 

In  view  of  our  knowledge  of  the  facts,  we  cannot  think  that  it  is  right  to 
assert  that  all  petroleums  and  asphalts  have  been  formed  by  any  one  method. 
It  seems  more  probable  that  all  of  the  theories  deriving  bitumens  from 
organic  substances  have  in  them  something  of  truth,  and  that  primarily  some 
have  been  derived  from  original  deposits  of  limestone,  some  from  sandstones, 
and  others  from  shales  or  clays  or  from  deposits  of  fairly  pure  vegetable  or 
vegetable  and  animal  matter;  and  further,  that  the  decomposition  has  some- 
times been  assisted  by  volcanic  or  other  heat  of  considerable  intensity, 
although  in  most  cases  the  attendant  heat  has  been  slight. 

The  enormous  supply  of  natural  gas  and  petroleum  has  led  to  the  suppo- 
sition that  they  cannot  be  derivatives  from  organic  life,  and  theories  have 
been  offered  to  account  for  their  formation  in  other  ways. 

A  chemical  theory  proposed  by  Berthelot  in  1866  is  worthy  of  mention. 
This  presupposes  the  existence  of  a  vast  quantity  of  hot  metals  in  the  interior 
of  the  earth  at  a  great  depth,  and  the  admission  to  them,  through  fissures  in 
the  earth's  crust,  of  water  charged  with  carbon  dioxide— a  very  abundant 
occurrence.  Under  these  conditions,  it  is  believed  that  various  hydrocarbons 
would  be  formed  which  would  ascend  and  permeate  beds  of  porous  rocks. 


This  theory  would  account  for  a  deep-seated  and  continuous  formation 
of  oil  and  gas.  We  know  that  most  oils  are  produced  by  the  decomposition 
of  organic  materials,  and  can  only  say  that,  while  it  may  not  be  impossible,  it 
is  highly  improbable  that  any  have  ever  been  generated  by  chemical  means 
from  inorganic  matter. 

HISTORY. 

There  are  references  to  the  use  of  asphalt  in  the  earliest  times  of  which 
we  have  any  record.  In  the  Bible  (Gen.,  vi,  14:  xi,  3:  xiv,  10)  the  asphalt 
which  is  still  yielded  by  springs  in  the  Euphrates  Valley  is  referred  to  as  the 
material  used  to  "  pitch  the  Ark,"  and  as  a  mortar  in  building  the  Tower  of 
Babel.  Nineveh  and  Babylon  used  this  same  mineral  pitch  or  asphalt  as 
cement  in  construction-work.  These  springs  or  "fountains  of  pitch  "  were 
described  by  Herodotus. 

The  Dead  Sea  occupies  the  place  of  what  was  in  olden  times  called  the 
"Vale  of  Siddim,"  and  it  was  from  this  neighborhood  that  most  of  the 
asphalt  was  obtained  by  the  Greeks  and  Egyptians.  The  ancient  name  of 
the  Dead  Sea  was  Lacus  Asphaltites. 

In  Egypt,  asphalt  was  used  as  cement  in  building  and  for  waterproof 
lining  in  cisterns,  and  silos  for  grain,  and  in  embalming  the  bodies  of  the 
dead.  Aristotle  and  others  called  it  "asphaltos;"  Pliny  referred  to  it  as 
"  bitumen." 

Petroleum  was  used  as  a  source  of  light  in  China,  Persia  and  India  at  a 
very  early  date. 

In  the  United  States,  crude  petroleum  was  used  by  the  Indians  for 
medicinal  purposes  before  the  whites  entered  the  country;  but  up  to  1850, 
and  considerably  later,  its  value  as  a  fuel  and  illuminant  was  not  recog- 
nized. 

The  asphalt  in  California  was  used  by  the  aboriginal  inhabitants  as  a 
cement  and  for  making  their  canoes  water-tight.  More  than  one  hundred 
years  ago,  the  priests  at  Spanish  missions  used  it  for  making  floors,  walls, 
roofs,  reservoirs,  and  water  conduits.  Among  the  Mexicans  it  found  a 
limited  use  for  paving,  but  there  was  little  employed  in  this  way  until  1880, 
and  not  till  1888  was  mining  done  on  a  large  scale. 

In  1832,  Count  Sassenay  called  attention  to  the  bituminous  limestone  in 
the  valley  of  the  Rhone,  and  in  1838  the  first  sidewalks  of  rock  asphalt  from 
Seyssel  and  Val  de  Travers,  were  laid  in  Paris.  It  was  tried  in  London  in 
1869  and  in  New  York  and  Washington  about  1872.  When  the  pavements, 
laid  with  rock  asphalt  from  the  French  quarries,  proved  satisfactory,  trials 
were  made  of  other  asphalts  for  paving.  Owing  to  a  lack  of  experience  and 
want  of  knowledge  of  the  variable  nature  of  the  many  similar  articles,  a  large 
number  of  the  pavements  first  laid,  proved  worthless. 

As  later  experience  has  taught  the  advantages  and  disadvantages  of  dif- 
ferent varieties,  and  the  proper  methods  of  preparing  the  crude  asphalt  and 
laying  the  pavement,  the  popularity  of  these  roadways  has  increased,  and  at 
the  present  time  asphalt  is  almost  without  a  rival  in  popular  esteem  as  a 
road-making  material  for  cities. 


USES. 


The  purposes  for  which  asphaltums  are  used  are  many  and  varied,  and 
depend  on  the  composition  and  texture.  In  brief,  they  may  be  classified 
as  follows:  (i)  For  varnish  and  paint;  (2)  for  insulating;  (3)  for  water- 
proofing; (4)  for  cement. 

For  making  black  japan  and  other  varnishes  and  black  paints,  the  pure 
varieties  are  used,  mixed  with  turpentine  and  linseed  oil  in  proper  propor- 
tions, sometimes  with  the  addition  of  shellac  and  other  substances. 

For  insulating,  some  kinds  of  asphalt  are  unsurpassed,  gilsonite  in  par- 
ticular being  remarkable  for  its  resistance  to  the  passage  of  the  electric 
current. 

Asphalts  have  been  used  as  a  substitute  for  rubber  in  the  manufacture  of 
garden  hose,  for  lubricating  purposes,  and  as  a  protective  covering  for  metals 
from  the  corrosive  action  of  salt  water  and  acids. 

As  a  waterproof  covering  and  a  cement,  its  uses  are  closely  allied.  On 
account  of  its  waterproof  property,  it  is  employed  as  a  preservative  for  wood 
and  metal  in  places  exposed  to  dampness,  preventing  wood  from  rotting  and 
iron  from  rusting. 

As  a  waterproof  cement,  it  is  used  in  the  construction  of  walls,  roofs, 
cisterns  and  viaducts,  being  sometimes  put  in  the  joints  between  stones  or 
bricks,  and  sometimes  spread  in  a  layer  over  the  exposed  surface. 

Felt  saturated  with  asphalt  is  extensively  used  for  roofing,  being  laid  on 
the  roof  and  covered  with  hot  asphalt  and  gravel. 

It  is  as  a  paving  material  that  asphalt  is  most  important,  95  per  cent,  of 
all  produced  being  utilized  in  this  way.  Its  value  for  paving  is  primarily  on 
account  of  its  cementing  power  and  because  the  cement  which  it  forms  is 
strong,  durable,  impervious  to  moisture,  unaffected  by  frost  or  by  heat  (up 
to  450°  F. ),  and  moderately  elastic.  Pavements  of  stone  or  wooden  blocks 
are  often  laid  on  a  foundation  of  asphalt  concrete,  with  hot  asphalt  as  a 
cement  run  in  the  joints  between  the  blocks. 

Sheet  asphalt  pavement,  when  properly  laid  of  good  materials,  forms  a 
roadway  with  a  perfectly  smooth  surface,  which  is  hard  without  being  brittle, 
durable,  resilient,  less  noisy  than  stone  or  brick,  more  easily  kept  clean  and 
free  from  dust  than  macadam  or  any  other  paving  material,  and  more 
hygienic  than  wooden  blocks  on  account  of  being  waterproof.  Larger  loads 
can  be  drawn  over  sheet  asphalt  than  over  any  other  roadway  with  the  same 
power.  Repairs  can  be  made  to  sheet  asphalt  with  less  trouble  and  expense 
than  to  almost  any  other  pavement. 

Like  everything  else,  it  has  some  defects,  but  it  is  conceded  that  these 
are  more  than  atoned  for  by  its  virtues.  On  account  of  its  smooth  surface 
(one  of  its  great  points  of  merit)  it  becomes  slippery  when  wet  or  when 
covered  with  frost,  but  the  newer  asphalt  pavements  are  less  slippery  when 
wet  than  those  which  were  laid  some  years  ago,  because  of  improved 
methods  of  preparing  the  composition.  The  firm,  smooth  surface  does  not 
afford  as  good  a  foothold  for  horses  as  loose  earth,  or  a  rough  pavement,  or 
even  macadam,  but  this  is  made  up  for,  by  the  greater  ease  with  which  loads 
are  drawn  over  it.  The  smoothness  adds  greatl)r  to  the  pleasure  of  riding,  and 
lessens  the  wear  and  tear  on  vehicles  occasioned  by  jolting  over  rough  roads. 


When  the  asphalt  is  not  properly  prepared  and  mixed,  and  not  laid  with 
the  greatest  care,  the  pavement  is  liable  to  the  formation  of  a  wavy  surface 
and  transverse  cracks,  to  decomposition  in  the  cracks  and  in  gutters,  to 
softening  in  hot  weather  and  brittleness  in  cold. 

The  preparation  of  asphaltum  for  paving,  or  indeed  for  any  purpose,  is 
a  process  requiring  great  care  and  an  intimate  knowledge  of  the  properties 
of  the  asphalt  in  question,  as  well  as  the  properties  which  are  requisite  in  the 
use  to  which  it  is  to  be  applied.  Chemical  analysis  and  tests  of  the  con- 
sistency and  cementing  power  must  be  made  in  order  to  learn  its  true  nature, 
and  the  best  results  are  never  attained  except  after  many  experiments. 

All  asphalt  pavements  are  composed  of  at  least  80  per  cent.,  and  more 
often  85  to  90  per  cent,  or  more,  of  sand  or  rock  held  together  by  asphaltic 
cement. 

Many  rock  asphalts  in  their  natural  state  approximate  this  composition. 
The  European  bituminous  limestones  run  from  7  to  20  per  cent,  bitumen, 
and  average  about  14  per  cent.  These  are  fine-grained,  compact  noncrys- 
talline  limestones,  and  experience  has  shown  that  they  form  the  best  pave- 
ment when  the  rock  contains  about  9  per  cent,  of  bitumen.  The  desired 
percentage  is  generally  reached  by  mixing  limestones  containing  greater  and 
less  percentages,  and  sometimes  by  adding  Trinidad  or  other  purer  asphalt 
to  a  low  grade  bituminous  rock.  The  mere  relation  of  bitumen  to  rock  in 
any  paving  material  may  be  misleading,  as  a  great  deal  depends  on  the 
character  of  the  rock,  whether  gritty,  fine  or  coarse,  and  even  grained,  and 
much  depends  also  on  the  character  of  the  bitumen  as  to  its  cementing 
power,  firmness,  and  liability  to  decomposition.  No  bitumen  used  for  paving 
ought  to  contain  much  oil  volatile  at  400°  F.,  and  the  dense,  rather  coarse- 
grained limestones  are  the  best.  Pavements  of  rock  asphalt  are  generally 
laid  on  a  foundation  of  concrete.  The  limestone  is  powdered  (if  necessary, 
mixed,  to  obtain  the  needed  percentage  of  bitumen)  and  heated  to  about 
275°  F.,  in  order  to  soften  the  asphalt,  so  that  when  it  hardens  it  will  cohere 
tightly  and  form  a  solid  mass.  The  hot  rock-asphalt  powder  is  spread  in  an 
even  layer  on  a  concrete  base,  and  immediately  rammed  down  with  heated 
rammers,  then  sprinkled  with  a  thin  layer  of  Roman  cement,  and  finally 
rolled  with  heavy  rollers.  The  final  thickness  of  the  asphalt  coating  is 
usually  from  one  and  a  half  to  two  and  a  half  inches. 

The  general  method  of  procedure  for  laying  pavements  of  any  rock 
asphalt  is  much  the  same  as  the  preceding,  whether  the  material  be  lime- 
stone or  sandstone.  The  bitumen  in  some  rock  asphalts,  such  as  that  from 
La  Patera,  California,  is  of  a  hard  nature  and  does  not  soften  sufficiently 
under  the  influence  of  a  gentle  heat,  usually  because  of  the  presence  of  too 
little  petrolene.  These  hard  asphalts  are  said  to  require  a  "flux"  (or,  in 
other  words,  the  addition  of  some  petrolene)  to  dissolve  the  asphaltene,  lower 
the  melting-point,  and  increase  the  cementing  power.  The  flux  in  most  gen- 
eral use,  and  which  is  most  available,  is  heavy  petroleum  oil.  This  is  a 
residue  obtained  from  crude  petroleum  by  the  distillation  of  the  lighter  oils. 
It  should  be  especially  prepared  for  paving  purposes,  not  all  of  such  residues 
being  suitable  for  this  use,  many  of  them  being  objectionable  on  account  of 
the  imperfect  removal  of  the  light  oils  or  the  presence  of  solid  paraffins. 


The  specific  gravity,  flash-point  and  melting-point  of  the  heavy  petroleum 
are  important  features  in  determining  the  suitability  as  a  flux. 

A  liquid  asphalt  from  California  is,  by  some,  considered  superior  to  the 
petroleum  residuum  for  use  as  a  flux,  on  account  of  the  frequent  presence  in 
the  latter  of  small  amounts  of  the  light  oils,  which  evaporate  after  the  pave- 
ment is  laid  and  weaken  the  cementing  power  of  the  asphalt. 

When  hard  asphalts  are  carefully  melted  with  the  right  kind  of  flux,  in 
the  correct  proportion,  they  absorb  it  readily,  and  form  a  tough,  strong  and 
elastic  cement. 

In  the  United  States,  particularly  in  the  East,  Trinidad  asphalt  is  the 
material  most  in  favor.  For  a  long  time  it  was  much  easier  to  obtain  this 
asphalt  than  any  other  kind,  and  so  many  good  pavements  have  been  laid 
with  it  that  it  is  considered  perfectly  reliable,  when  prepared  and  laid  with 
care. 

As  mined,  the  Trinidad  lake  pitch  is  a  dark-brown  substance,  which  is 
solid  enough  to  flake  off  easily  with  a  pick  and  is  seldom  at  all  sticky.  In 
spite  of  its  apparent  solidity,  it  flows  very  slowly,  and  a  heap  of  it,  if  allowed 
to  do  so,  will  spread  out  gradually  and  flow  in  every  direction,  at  the  same 
time  retaining  its  solid  appearance.  In  its  crude  state,  it  contains  about  55 
per  cent,  bitumen  and  28  per  cent,  water,  the  remaining  17  per  cent,  being 
very  finely  divided  earthy  matter  with  a  little  undecomposed  organic 
material.  For  use  it  must  be  refined,  a  process  which  consists  primarily  in 
removing  the  water,  and  the  little  unaltered  organic  matter,  which  it  con- 
tains. The  refining  is  done  by  melting  the  asphalt  and  driving  off  the  water 
by  heat,  the  other  impurities  being  skimmed  off  the  top.  During  the  melt- 
ing, the  temperature  should  never  exceed  400°  F.,  as  a  greater  heat  is  likely 
to  injure  the  quality  of  the  asphalt.  In  the  best  refining  processes,  large 
kettles  holding  twenty-five  tons  or  more  of  the  crude  asphalt  are  heated  by 
coils  of  steam  pipes  so  arranged  as  to  heat  the  entire  mass  evenly.  While 
melted,  the  asphalt  is  kept  in  continual  agitation,  to  prevent  the  separation 
of  the  earthy  matter  contained  in  it. 

When  cool,  this  refined  asphalt  is  black,  hard  and  brittle,  and  must  be 
melted  with  a  flux  in  order  to  form  a  cement  of  sufficient  strength.  The 
heavy  petroleum  before  alluded  to  is  employed,  being  mixed  with  the  melted 
asphalt  in  the  proportion  of  from  15  to  21  pounds  of  residuum  oil  to  100 
pounds  of  refined  asphalt,  and  the  heated  mixture  is  thoroughly  agitated  for 
several  hours  by  a  current  of  air  in  order  to  obtain  a  homogeneous  material. 
This  is  called  asphaltic  cement,  and  is  carefully  tested  in  an  ingenious  ap- 
paratus in  order  that  it  may  have  the  consistency  which  gives  it  the  desired 
cementing  value. 

The  foundation  for  Trinidad  sheet  asphalt  paving  is  a  four  to  six  inch 
bed  of  concrete,  composed  of  broken  stone,  sand  and  hydraulic  cement.  In 
order  that  the  wearing  surface  may  adhere  firmly  to  the  concrete  base,  it  has 
been  found  advisable  to  lay  on  the  concrete,  a  binder  layer  of  small  broken 
stone  mixed  with  asphaltic  cement.  This  binder  layer  is  put  down  hot  and 
rammed  and  rolled  till  it  is  firm  and  smooth,  and  usually  is  about  one  and  a 
half  inches  thick. 


14 

The  top  or  wearing  surface  is  practically  an  artificial  sandstone.  It  is 
prepared  by  mixing  the  previously  described  asphaltic  cement  with  sharp, 
clean  quartz  sand  and  limestone  dust  in  the  proportion  of  asphaltic  cement 
13  to  16  parts,  sand  79  to  84  parts,  and  limestone  dust  3  to  5  parts. 

The  ingredients  are  mixed  at  a  temperature  of  about  300°  F.,  and  it  is 
very  important  that  the  mixture  of  the  cement  and  mineral  matter  shall  be 
complete  and  uniform,  so  that  each  particle  of  sand  is  entirely  covered  by 
the  cement  in  order  to  obtain  the  perfect  cementation  and  uniform  texture 
that  is  wanted.  It  is  found  desirable  to  retain  in  Trinidad  asphalt  the  earthy 
particles  that  it  contains,  on  account  of  their  natural  perfect  union  with  the 
bitumen.  This  mixture  for  the  wearing  surface  is  spread  as  a  hot  powder, 
in  an  even  thickness  upon  the  binder  layer,  first  rammed,  and  then  rolled 
with  heavy  steam  rollers  until  it  is  solid,  and,  as  usually  laid,  it  has  a  final 
thickness  of  from  one  to  two  inches.  Other  foundations  than  concrete  are 
sometimes  employed,  usually  an  old  pavement  of  another  kind,  the  wearing 
surface  being  laid  with  or  without  binder  layer  on  a  payement  of  stone 
blocks,  macadam,  wooden  blocks,  asphalt  blocks  or  brick. 

Asphaltum  in  some  other  forms  has  found  a  limited  use  in  paving. 

Mastic  (asphalte  coule)  consists  of  the  powdered  bituminous  limestone 
mixed  with  about  8  per  cent,  of  Trinidad  asphalt,  and  then  moulded  into 
blocks.  For  use,  these  blocks  are  broken  up  and  melted  with  asphaltic 
cement  and  mixed  with  sand  and  gravel.  The  mixture  is  a  hot  fluid,  and  is 
poured  on  a  foundation  in  an  even  layer  and  allowed  to  harden.  Mastic 
pavements  are  chiefly  employed  for  sidewalks. 

Asphalt  paving  blocks  are  composed  of  a  mixture  of  Trinidad  asphalt 
and  crushed  stone,  moulded  and  pressed.  These  blocks  are  easier  to  lay  than 
sheet  asphalt,  and  while  not  nearly  so  durable,  they  are  well  adapted  to  light 
traffic. 

The  proper  treatment  of  other  asphaltums  depends  in  each  case  on  the 
nature  of  the  substance  itself.  Some  are  so  pure  as  not  to  need  refining,  and 
each  variety  requires  its  own  treatment  in  order  to  obtain  satisfactory  results. 

In  Europe  the  bituminous  limestones  have  been  mostly  used  for  paving, 
and  in  the  central  and  western  parts  of  the  United  States  bituminous  sand- 
stones have  been  largely  employed.  In  the  eastern  part  of  this  country,  and. 
to  a  greater  or  less  extent  in  other  parts  of  the  world,  the  Trinidad  asphalt 
has  been  received  with  much  favor.  On  account  of  being  mixed  with  sharp 
sand,  the  surface  of  the  Trinidad  asphalt  pavements  is,  as  a  rule,  less 
slippery  than  those  in  which  rock  asphalts  are  used,  the  fine-grained  lime- 
stones being  most  objectionable  in  this  regard. 

Many  cities  have  elaborate  specifications  in  regard  to  the  materials 
which  may  be  used  in  asphalt  paving,  their  proportions,  and  the  processes  of 
preparing  and  laying.  These  specifications  are  prepared  by  persons  familiar 
with  the  proper  treatment  of  a  certain  kind  of  asphalt,  and  for  this  reason 
generally  put  the  paving  in  the  hands  of  one  company,  or,  at  any  rate,  pre- 
vent the  use  of  any  asphalt  other  than  the  one  for  the  use  of  which  the 
specifications  were  constructed,  because  no  two  asphaltums  have  identical 
composition,  texture  and  properties,  and  each  one,  therefore,  requires  different 
treatment  to  obtain  the  best  results. 


15 

After  short  trials,  many  asphalts  have  been  condemned,  some,  no  doubt 
justly,  because  of  lack  of  cementing  power  or  liability  to  decompose;  but  it 
should  be  remembered  that,  owing  to  improper  treatment,  some  very  poor 
pavements  have  been  laid  with  good  materials. 

Often,  careful  study,  intelligent  experiment,  and  proper  methods  of 
preparing  and  laying  the  materials  will  result  in  first-class  pavements  with  a 
material  which  has  at  first  been  deemed  unsatisfactory. 


16 


ANALYSES. 


PURE   BITUMENS. 


IyOCAUTY. 

Carbon 

Hydrogen. 

1 
Oxygen. 

Sulphur. 

i 

jj 

Bitumen      from      Trinidad      lake 

asphalt  
Bitumen      from     Trinidad      land 

82.33 

10.69 

6.16 

o.Si 

asphalt  

83.68 

10.84 

5-10 

0.45 

Bermudez  (soft)  

82.88 

10.79 

5.87 

0.75 

Bakersville  (California)  maltha     . 

84.31 

12.41 

•1.40 

.  .  . 

Bitumen  from  Seyssel  limestone  . 

85.00 

12.  OO 

3.00 

Auvergne,  France  
Cuba  

77.64 
82.34 

7.86 
9.10 

8-35 
6.25 

1.  02 

1.91 

5.13 

0.40 

Peru    
Ozocerite   Galicia 

88.66 
8s  so 

9.69 
14.  So 

1.65 

.  .  . 

Ozocerite,  Utah   

O  *  3 

85-44 

m*t*  C) 

H-45 

Uintahite,  Utah  

80.50 

10.00 

6.20 

3.30 

Gilsonite,  Utah    

88.30 

9.90 

1.96 

Albertite,  Nova  Scotia  

86.04 

8.96 

1.97 

2.93 

Grahamite,  West  Virginia    .... 

79.00 

6-5 

14.00 

Elaterite,  England     
Petrolene 

83.62 
87  iq 

11.19 

12.  6l 

4.78 

0.24 

0.17 

**/  0:7 

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WORLD'S  PRODUCTION  OF  ASPHALT. 

1897. 
In  metric  tons  (2204.6  pounds). 

ASPHAI/TUM. 


Tons. 

Trinidad     

....  133,310 

United  States    

....    24,854 

Russia    

....    18,000 

Venezuela  

....     11,528 

Hungary    

•        •    •      3,057 

190,749 

ASPHAI/T   ROCK. 

Tons. 

Germany    

....     61,645 

Italy    

....     54,647 

United  States    

....     51,670 

France    

...     30,946 

Spain  

....        1,656 

Austria   

....           300 

200,864 

PRODUCTION  OF  ASPHALT  IN  THE  UNITED  STATES. 

1898. 
In  short  tons  (2000  pounds). 

BITUMINOUS   SANDSTONE. 

Tons.  Dollars. 

California 46,836  137,575 

Kentucky 2,700  8,700 

49,536  146,275 
BITUMINOUS  UMESTONE. 

Tons.  Dollars. 

Utah 150  750 

Indian  Territory 13,949  69,745 

14,099  70,495 

ASPHAI/TUM. 

Tons.  Dollars. 

California 25,690  482,175 

UINTAHITE,  ETC. 

Tons.  Dollars. 

Utah 2,675  80,250 

IMPORTS  OF  TRINIDAD  ASPHALT  TO  THE  UNITED  STATES. 

In  long  tons  (2240  pounds). 

1897.  1898. 

Tons.  Tons. 

Lake  asphalt 73,73s  47,78i 

Land  asphalt 19,243  18,160 


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